Nevertheless, this is the right merger at the right time. It should just be the last among major carriers.

For many of the 35 years since the industry was deregulated, airlines have been in a state of near chaos. American Airlines is fighting its way out of Chapter 11 bankruptcy. Its would-be partner, US Airways, has been in and out of the process twice. Counting airlines such as TWA, America West and Ozark that those two airlines had acquired, the new behemoth would count at least six bankruptcies in its history.

This is no way to run an industry, as exasperated fliers will attest. But it's the norm. United, Delta and a host of other airlines have gone through a Chapter 11 restructuring. And a number of long-forgotten carriers have met their ends in Chapter 7 liquidations. It's harder to name airlines that never went through bankruptcy than those that did. Southwest is the lone major example.

Strapped for cash and often laden with debt, the airlines have struggled to maintain customer service and to raise the money needed to purchase or lease aircraft.

An American-US Airways merger would not solve all these problems. But it can be the last leg in bringing the industry much-needed stability.

For years, it has been clear to many airlines watchers that the industry was inevitably heading toward an equilibrium of three major hub-and-spoke carriers. Any more would mean at least one would be struggling at any given time. Any fewer would not be tolerated by the Justice Department's antitrust division, which usually lets an industry drop from four competitors to three, but equates a drop from three to two with abusive practices.

The three survivors, meanwhile, will continue to face stiff competition from point-to-point airlines such as Southwest, and niche carriers such as JetBlue and Virgin America, restraining fare hikes.

The proposed merger, like those before it, will also provide at least one direct benefit to consumers: more cities to fly to.

Air travelers have long wanted low fares. But they have been equally adamant that their preferred carrier - the one on which they have amassed the most frequent-flier miles - fly to a wide array of cities. That was hard to find in the past with multiple carriers, and to some degree it can still be difficult to find.

Travelers who live in parts of the eastern United States, for instance, might find that US Airways is the dominant airline and is fine for getting to other places on the East Coast. But if they need to get out West, their options are limited. With the merger, they'd find a lot more options for getting around. And despite the fact that the two carriers would make up the world's largest by revenue, they currently overlap on just 13 routes.

On the downside, airline mergers can lead to a painfully slow process of combining reservations systems and staffs. The recent merger of United and Continental is a case study of how many glitches these mergers can have. US Airways chief Doug Parker, expected to be CEO of the merged airline, has led several mergers and should be able to speed the transition.